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Quiz: What's Your Body IQ?

Quiz: What's Your Body IQ?

From brain circuitry that's more intricate than the most sophisticated computer to heart muscles that can pump nonstop for decades, your body is truly a wonder. But chances are you haven't given its little miracles much thought since you were last quizzed on them for high school biology class.

So just how well do you remember your body's complex and extremely impressive mechanics? Test yourself on the basics with this head-to-toe photo quiz — then feel free to amaze your kids and friends with the "did you knows?" that are sure to follow.

Photo credit: Oliver Burston/Photolibrary

Additional reporting by Ashlee Davis

If lined up end to end, these body parts would extend for 100,000 miles.

Answer: Blood Vessels

An adult's arteries, veins, and capillaries, through which your blood circulates, would wrap around the globe a whopping four times, according to the Franklin Institute in Philadelphia. The blood vessels of an average child stretched end to end would measure about 60,000 miles long.

Health tip: One of the best ways to protect your blood vessels and heart is to keep your blood pressure (the force blood exerts on your artery walls as it pumps through your body) in check. Elevated blood pressure can raise your risk of heart attack, stroke, and kidney problems. About one in three Americans has high blood pressure, but half aren’t treating it properly, according to the U.S. Centers for Disease Control and Prevention. Here's how to lower blood pressure naturally.

These organs contain 600 million tiny sacs.

Answer: Lungs

About 300 million alveoli, or tiny air sacs, fill each of your lungs, according to the Science Museum of Minnesota in Saint Paul. In the alveoli occurs the crucial two-fold exchange that keeps your body running smoothly: Oxygen from the air you breathe moves into your blood, and carbon dioxide waste exits your blood to be exhaled through your lungs.

Health tip: Although smoking cigarettes permanently damages the alveoli and can make breathing, especially exhaling, difficult, quitting smoking will improve your lung health. Within just three days of kicking a smoking habit, the bronchial tubes that lead to the alveoli begin to relax, making breathing easier.

Photo credit: Garry Hunter/Getty Images

This body part contains 26 bones, 33 joints, and more than 100 muscles, tendons, and ligaments.

Answer: Foot

They may be small in size, but your feet are designed as well as a race car, according to the American Podiatric Medical Association. Thanks to all of those bones, joints, and muscles, the foot can withstand an impressive amount of pressure. Just walking around each day exerts a force on your feet equal to several hundred tons!

Health tip: Paying attention to your foot health can provide valuable clues to your overall health. Joint stiffness in your toes could mean arthritis, tingling or numbness could indicate diabetes, and swelling may be a sign of kidney disease, heart disease, or high blood pressure, according to the National Institute on Aging.

Photo credit: Getty Images

This body part moves up to 144,000 times a day.

Answer: Heart

How often your heart beats at rest is a measurement known as your resting heart rate, or pulse. A healthy resting heart rate ranges from 60 to 100 beats per minute (bpm), according to the Mayo Clinic — or about 86,000 to 144,000 times each day — but the lower, the better. In fact, one study published in the British Medical Journal of postmenopausal women free of heart disease found that those with the highest resting heart rates (above 76 bpm) were about 25 percent more likely to have a heart attack than women with the lowest (62 bpm or less).

Health tip:To lower your resting heart rate, exercise more. The fitter you are, the less hard your heart has to work to pump blood. A super-fit athlete may have a pulse closer to 40 bpm.

Photo credit: MEDI-MATION/Getty Images

There are 22 bones in this body area.

Answer: Head

The cranium, which protects your brain, is comprised of eight bones, while your face is made up of 14 bones, according to Columbia University Press. A baby is born with all eight cranial bone plates, but to allow room for the brain to grow they’re not completely fused together. By age 2, the "soft spots" on the top of a baby's head disappear when the bones have grown long enough to meet, but they don’t fully fuse until around age 20.

Health tip: Keep the brain that those bones protect sharp by challenging your mind on a daily basis, like taking a different route home from work, doing a crossword puzzle, or trying a new class at the gym.

Photo credit: Getty Images

You produce 2 to 4 pints of this fluid each day.

Answer: Saliva

Also known as spit, drivel, and drool, saliva is 98 percent water and a 2 percent mix of electrolytes, mucus, antibacterial compounds, and enzymes, according to KidsHealth.org. Saliva's primary purpose is to jump-start digestion by helping to break down food in the mouth before you swallow it. It also aids your taste buds — without saliva, you wouldn’t be able to taste anything.

Health tip: If you don't produce enough saliva, you may be left with a sticky feeling known as dry mouth. Chewing gum, using a humidifier, and avoiding alcohol, tobacco, and caffeine can help moisten your mouth. Dry mouth can also be caused by certain medications and health issues, such as diabetes.

Photo credit: Corbis

This body part moves around 15,000 times each day.

Answer: Eyelid

Blinking is your bod'’s way of cleaning out your eyes and removing irritants. Most people blink between 10 and 15 times per minute, according to the University of Pennsylvania Health System in Philadelphia, but you may blink less when you stare at a computer or more when under stress. This can be especially noticeable during political debates: Presidential hopeful John McCain made headlines after a 2008 debate against Barack Obama, when he reportedly blinked more than 3,000 times during the 90-minute session, or 33 blinks each minute.

Health tip: If you find yourself blinking a lot more than usual, you may have dry eye syndrome, which can be caused by contact lens irritation and medications like decongestants and antidepressants. Using artificial tear drops or ointments and consuming more omega-3 fatty acids (from supplements or fish like salmon) can help.

Photo credit: Corbis

This body part hosts the smallest bone in your body.

Answer: Ear

You can’t see it, but the smallest bone in your whole body is called the stirrup, and it’s the size of a teeny half-grain of rice, according to American Bone Health. Located in the ear behind your eardrum, the stirrup works with the hammer and anvil bones to help interpret sound waves when the eardrum vibrates.

Curious what the largest bone is? It’s the femur, in your thigh.

Health tip: Although hearing problems tends to come with age (more than 30 percent of Americans over the age of 60 have hearing loss), you can protect your hearing by limiting your exposure to loud music and machines.

Photo credit: iStock Photo

These organs process 100 gallons of blood each day.

Answer: Kidneys

Each of your two kidneys has one million filters called glomeruli, which handle about 50 gallons of blood each per day, according to American Association of Kidney Patients. The one-half to two quarts of water and waste that are removed from the blood exit your body as urine.

Health tip: Among the best ways to keep your kidneys in tip-top shape (and prevent kidney disease and cancer): Maintain a healthy weight, don’t smoke, and treat high blood pressure and diabetes.

Photo credit: Ralph Hutchings/Getty Images

Trillions of bacteria call this body area home.

Answer: Gastrointestinal Tract

Of the roughly 100 trillion microbes that inhabit the human body, many of them live in the digestive tract. Most of these are “good” bacteria that aid digestion by breaking down nutrients and support the immune system by defending against invading germs. In fact, about 75 percent of your body’s immune system cells are located in your digestive tract.

Health tip: Consuming foods such as yogurt that contain probiotics, or “good” bacteria, can help maintain the proper ratio of good to bad bacteria in your gut, which prevents tummy trouble like bloating and diarrhea. This is especially important when you're taking antibiotic medications, which can disrupt your natural balance.

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